The phone number is on the SIM card if it is a GSM phone. When you rekove the SIM card, the phone will have no number.

By the way, why did you choose your user name as the title of your message?

motorola w376g, this is for tracfone I bought this phone on ebay and when I went to register it it wouldn't work. I got to checking and found out it has someone else phone number on it, it also has the sims card but is not registered. How do I get the old phone number off so I can register it in my name? Thanks Don